This invention relates generally to motorcycles and more particularly to two-wheeled motorcycles of the type including a streamlined cowling structure arranged to cover the rear-wheel driving power unit.
In the past, with two-wheeled motorcyles of the type concerned, the cowling structure has only been used to cover the power unit to serve the purpose of reducing the air resistance of the vehicle during travel and has not been intended to serve as a strength member of the vehicle frame. Therefore, the use of such cowling structures has unavoidably resulted in an increase in vehicle weight.
On the other hand, with two-wheeled motorcycles, any slight difference in vehicle weight has a large influence on the different vehicle performances such as acceleration and maneuverability, and the use of a cowling structure involving increase in vehicle weight is undesirable.